Reply to thread

Message

[QUOTE=&quot;Piggie, post: 45445, member: 2941&quot;]Yeah, brain fart. 1/4 dipole. sorry. 1/8 wave FM antennas?&nbsp; You mean a 15 inch whip?&nbsp; Most likely if an FM antenna has a built in telescoping whip less than 30 inches it most likely has a matching network. I have always felt the reason the 4228A has VHF response is the resonance of the reflector couples into the driven elements by &quot;force&quot;, even though the elements are tuned to UHF.I don't know the math with out research but the impedance of a 1/4 dipole would be such a mismatch to the matching network in a N-Bay, I can't see it being anything of a tuned input.&nbsp; Much like if you live near a TV station you can receive VHF on a paper clip. Enough RF and anything will couple.In other words the reflector does the work of resonating at high band. Then UHF elements just couple that energy (capacitively and probably inductively as well to a degree) to the coax.I have never seen anywhere any reference to a 1/4 wave resonator&nbsp; center feed that didn't need a matching network. Talk me down but I believe it's purely coupling between the reflector and the feed system.Yes the bowtie design is a take off from the old muli-wire dipoles providing a longer resonance point, agreed. But there is a limit to how far they broadband. Antennas in general will work at odd harmonic very well, but no sub harmonics.[/QUOTE]

[QUOTE="Piggie, post: 45445, member: 2941"]Yeah, brain fart. 1/4 dipole. sorry. 1/8 wave FM antennas? You mean a 15 inch whip? Most likely if an FM antenna has a built in telescoping whip less than 30 inches it most likely has a matching network. I have always felt the reason the 4228A has VHF response is the resonance of the reflector couples into the driven elements by "force", even though the elements are tuned to UHF. I don't know the math with out research but the impedance of a 1/4 dipole would be such a mismatch to the matching network in a N-Bay, I can't see it being anything of a tuned input. Much like if you live near a TV station you can receive VHF on a paper clip. Enough RF and anything will couple. In other words the reflector does the work of resonating at high band. Then UHF elements just couple that energy (capacitively and probably inductively as well to a degree) to the coax. I have never seen anywhere any reference to a 1/4 wave resonator center feed that didn't need a matching network. Talk me down but I believe it's purely coupling between the reflector and the feed system. Yes the bowtie design is a take off from the old muli-wire dipoles providing a longer resonance point, agreed. But there is a limit to how far they broadband. Antennas in general will work at odd harmonic very well, but no sub harmonics.[/QUOTE]

Name

Verification